The present invention relates to intravaginal drug delivery devices made of polyurethane copolymers and to administering one or more pharmaceutically active substances to a patient in need thereof.
Drug delivery devices are specialized tools for the delivery of a drug or therapeutic agent via a specific route of administration. Such devices are used as part of one or more medical treatments. Examples of drug delivery devices include, but are not limited to, cardiovascular devices, ophthalmic devices, antivirus devices, dialysis devices, contraceptive devices, drug-eluting stents, catheter tubing, transdermal devices, and/or intra-uterine devices.
Drug delivery devices, such as intravaginal drug delivery devices, including intravaginal rings (IVRs), are typically formed from biocompatible polymers and contain a drug released by diffusion through the polymer matrix. The IVR devices may be inserted into the vaginal cavity and the drug may be absorbed by the surrounding body fluid through the vaginal tissue.
Poly(ethylene-co-vinyl acetate), or ethylene vinyl acetate (EVA) (used e.g. in NuvaRing), and poly(dimethyl siloxane), or silicone (used e.g. in Estring, Femring and in Population Councils progesterone-releasing ring), are currently commercially exploited for IVRs. Compared to poly(ethylene-co-vinyl acetate) or ethylene vinyl acetate (EVA), silicone is limited by a lower mechanical stiffness. Therefore, silicone IVRs are fabricated with larger cross-sectional diameters to achieve the retractive forces required for retention in the vaginal cavity, which may affect ring user acceptability. Moreover, the manufacturing costs associated with these IVRs are considerable. Both EVA and silicone have been found particularly useful for the release of a steroid which is a substantially water-insoluble drug.
Polyurethane-containing intravaginal rings have been described (See, Gupta, Kavita M. et all. Journal of Pharmaceutical Sciences (2008), 97(10), 4228-4239 and, and WO2009094573. The known polyurethane-containing IVRs are IVRs containing one single drug. Further, segmented polyurethane IVRs are described in WO2009003125 and WO2009094573.
In addition, the use of polyurethanes for drug delivery devices has been limited in part due to the high processing temperatures required for polyurethanes. These temperatures are often too high for thermolabile drugs.
It has also been found that EVA and silicone, which are both hydrophobic polymers, are not able to provide a desired release rate for hydrophilic drugs. So far, no intravaginal ring has been developed for the co-delivery of drugs with different hydrophilicity.